Matt - you've hit the nail on the head there mate - I never even gave it a thought
The rider 7b's have been up in the loft for a year and the nice ones with the heavy gauge spokes are down in the "build room" I just assumed they would both be the same but I digged the rider ones out of the loft and they've got normal spokes even though both sets are early ones with no size stamp on the rim
They both have shimano high flange hubs but the hubs on the heavy gauge jobbies are drilled larger for the heavy gauge spokes - you live and learn hey
I was surprised how much weight the heavy gauge spokes add
I weighed the front wheel of both sets without tyres :
With heavy gauge - 1100g
with normal spokes - 850g
What a difference - glad the rider ones are the lighter ones